Voodoo Main Discussion

[MartyJ1963]

Great work Alec! Looking forward to your upcoming video. I've had to take time out for a few days due to some serious repairs to the house that need to be done before Winter because it's already a little cold over here and they've forecast a colder Winter for Britain this year and maybe snow. I'm looking forward to the coil building stage though! Regards, Marty

[6666]

It's very difficult to get technical documentation 100% correct. I was reading an Arduino book recently, and discovered several errors. The book was published by a reputable publishing company, and their experienced proof readers still managed to miss stuff.

Its all good George.

[Math]

When I was discussing chatter in the book, I was referring to some of the experimental prototype versions. At one point (page 10) I state: "Eventually after much effort, the noise, instability, chatter, and timing issues were all resolved."

Ok George ive given the best i can with what i know on points 1/ to 4/ - areas for further R&D on the final page 83 of your book.

[Qiaozhi]

Ok George ive given the best i can with what i know on points 1/ to 4/ - areas for further R&D on the final page 83 of your book.

Thanks Matt, much appreciated. That was the reason for the further R&D points, to make people think about possible improvements.
Although any chatter caused by alignment of the two channels was resolved to my satisfaction, there can still be instances where some dubious targets can break through. This also happens with VLF detectors, with some being worse than others. I presume that's what you're actually referring to in your discussion.

[surfdetector]

Hybrid mode

Well done. That looks good.
The extra ringing is occurring during the TX-on time, and does not affect correct operation of the detector. Fig. 2-1 shows the result for a Troy coil, so the Fisher F75 coil may quite possibly be different.

This is a very good project. I thank you George for all of your hard work in researching and developing it for us. Here is a link to one of my videos which shows the Hybrid operation towards the end:
https://youtu.be/6im66f8PGbk

[lamoiz]

hi George, yes indeed my probe was 1: 1, tonight here is with 10: 1 probes. dc ..

[Qiaozhi]

hi George, yes indeed my probe was 1: 1, tonight here is with 10: 1 probes. dc ..
[ATTACH]53855[/ATTACH][ATTACH]53856[/ATTACH][ATTACH]53857[/ATTACH][ATTACH]53858[/ATTACH]

Looking at the images for Fig. 3-17 and Fig. 3-20, it looks like external noise to me. The scope images in the book were captured indoors, and (as you can see) the preamp output is relatively clean. The noise on your board is extremely bad.

What do you see at the output of the preamp with the coil disconnected? Also try with only the damping resistor fitted (no coil).

[lamoiz]

Looking at the images for Fig. 3-17 and Fig. 3-20, it looks like external noise to me. The scope images in the book were captured indoors, and (as you can see) the preamp output is relatively clean. The noise on your board is extremely bad.

What do you see at the output of the preamp with the coil disconnected? Also try with only the damping resistor fitted (no coil).

ok George, yes I have a lot of noise I will immediately measure without a coil to see

[lamoiz]

Looking at the images for Fig. 3-17 and Fig. 3-20, it looks like external noise to me. The scope images in the book were captured indoors, and (as you can see) the preamp output is relatively clean. The noise on your board is extremely bad.

What do you see at the output of the preamp with the coil disconnected? Also try with only the damping resistor fitted (no coil).

here are the horrors ...

[Qiaozhi]

here are the horrors ...[ATTACH]53859[/ATTACH][ATTACH]53860[/ATTACH][ATTACH]53861[/ATTACH]

It looks like the oscillations are being generated on the PCB.
Can you post an image of the main and EFE sample pulses? They should switch between -5V and +5V.

[Qiaozhi]

It looks like the oscillations are being generated on the PCB.
Can you post an image of the main and EFE sample pulses? They should switch between -5V and +5V.

As surfdetector has successfully replicated the Voodoo project, I have posted (as promised) the source code in post #1.
Although you can view the code using any text editor, you will need Mikroelektronika's mikroC Pro compiler to alter and recompile the hex.
If anyone wants to accept the challenge of converting this to Microchip's MPLAB XC8 compiler, then be my guest.

[6666]

This is a very good project. I thank you George for all of your hard work in researching and developing it for us. Here is a link to one of my videos which shows the Hybrid operation towards the end:
https://youtu.be/6im66f8PGbk

ID looks good on the bench, any plans to bury some targets and re test ?, congrats on getting it working.

[waltr]

As surfdetector has successfully replicated the Voodoo project, I have posted (as promised) the source code in post #1.
Although you can view the code using any text editor, you will need Mikroelektronika's mikroC Pro compiler to alter and recompile the hex.
If anyone wants to accept the challenge of converting this to Microchip's MPLAB XC8 compiler, then be my guest.

Thanks for posting the source.Looking through the code and quickly see that you used many build-in MikroC functions (libraries) that would need to be written in XC8.
First example is the function Lcd_Chr(row, col, value);
Others are ADC_Read(batt_adc); EEPROM_Write(0, 0xAA); EEPROM_Read(2); Lcd_Out(); ADC_Init(); Lcd_Init();


Plus there are none of the 'configuration bits' in the code.

This will NOT be easy to convert to XC8.......

[Mdtoday]

Thanks for posting the source.Looking through the code and quickly see that you used many build-in MikroC functions (libraries) that would need to be written in XC8.
First example is the function Lcd_Chr(row, col, value);
Others are ADC_Read(batt_adc); EEPROM_Write(0, 0xAA); EEPROM_Read(2); Lcd_Out(); ADC_Init(); Lcd_Init();


Plus there are none of the 'configuration bits' in the code.

This will NOT be easy to convert to XC8.......

@Waltr,

Actually, its not to bad at all asuming one uses the MCC for setting up common peripherals. It is mostly syntax changes on port and register defines etc and there are a couple of LCD libraries available free that can be used to replace the Mikro C version.

When I clear the decks of current projects, I'll do a port and share.

For example working with SFR or port pins..

ADCON0.ADON = 1; // ADC on is the Mikro c version of ADC enable
ADON = 1; // ADC on is the XC8 version of same



Here is the XC8 code for reading an ADC channel on the Pickini 4 project



void Read_Opamp_Out()
{

ADC_SelectChannel(Analog_Offset);
ADC_StartConversion();
while(!ADC_IsConversionDone());
DC_offset = ( ADC_GetConversionResult()>>3);

}


The EEprom example routine is

// Save the current DAC value in EEPROM for the start of a next
// calibration.
EEPROM_WRITE(0x00,DAC_value);


So not too bad.


Cheers

[Mdtoday]

For those interested;

Here is the HiTech C LCD library I modified slightly to use in a front panel I designed a little while ago.

Interfacing-LCD-with-PIC-Microcontroller-Hi-Tech-C (1).zip

You can modify it to use in XC8 as I have done to suit hardware in this project here;

PiPi_FP_Test.zip

Please note it is a test project, working but not optimised.
It is posted to help those who may wish to port George's code.

I also use the Mikro C Dongle Version Compiler from time to time so will build the hardware and use Mikro C first then do the port to XC8 later.
That way I know my way around the firmware and what it is doing rather than blindly porting it and having head scratching moments.

Well written book George, thank you for sharing.

Based on PIC16LF1829



Cheers